Spinning Process of Waterless Colored Heather Yarns

ABSTRACT

A method of forming a colored heather yarn, comprising the sequential steps: (a) processing a natural fiber; (b) producing a waterless dope-dyed man-made fiber; (c) blending the individual fibers from steps (a) and (b) to produce a blended composite of fibers; and (d) roving, spinning and winding the blended composite of fibers of step (c) into a final colored heather yarn; wherein the colored heather yarn comprises a predetermined fiber content ratio. There is also provided a colored heather yarn made according to the foregoing method.

TECHNICAL FIELD

The present invention generally relates to a method of forming a colored heather yarn. The present invention also relates to the colored heather yarn made according to the method as defined herein.

BACKGROUND OF THE DISCLOSURE

Textile manufacturing is one of the oldest human activities that have evolved throughout the years. It is considered as one of the major industries that have attracted abundance of attention. It is based on the conversion of different types of fiber into different types of yarn and then yarns into their respective types of fabric. In this regard, textile manufacturing includes several processes such as cultivating and harvesting, preparatory processes, spinning processes, weaving or knitting and finally finishing processes to obtain the desired textile.

Among the industrial methods used, there are certain processes that require high consumption of energy in the form of water and electricity, especially in processes like washing, de-sizing, bleaching, rinsing, dyeing, spinning, printing, coating and finishing. These processes are still not as environmental friendly as they should be. In particular, the two processes that utilize the highest amount of energy are dyeing and spinning processes. These two processes require high consumption of water due to the nature of their methods. Furthermore, during the preparatory processes such as carding, combing and/or drawing, the processes would cause the fibers to break easily, thus generating high fiber wastage. In addition, some of the dyeing processes also lack fastness properties, leading to demand that a more efficient and energy-saving method be developed to overcome these disadvantages.

Dyeing is the process of imparting colors to textile materials like fibers, yarns and fabrics through a dye (color). Dyeing is generally done in a special solution containing dyes and particular chemical materials. The more common methods of dyeing include direct dyeing, stock dyeing, top dyeing, yarn dyeing, dope dyeing and garment dyeing. Of these methods, direct dyeing and yarn dyeing are the most popular ones that require the use of aqueous solutions. More recently, methods for specific fibers were developed such as heat transfer printing for polyester fibers, which is a simple method to use and a highly economic process for polyester coloration. This process utilizes sublimation to disperse dyes that are either dissolved in a minimal amount of water or solvent at a temperature of about 210° C. The sublimation process is generally related to the relative molecular mass of the dyes: the smaller the dye molecules, the better the transferability onto polyester. Further, methods such as using ultrasonic energy in the dyeing process have also been widely studied due to improvements such as reducing energy cost. In particular, the Cold Pad Batch (CPB) dyeing method offers a most economical and convenient method of dyeing cotton with reactive dyes. The energy and water consumption are reduced and salt addition is eliminated, thus rendering it more eco-friendly and providing a high degree of dye fixation.

The other process that is of great concern is the spinning process which includes wet spinning, dry spinning, melt spinning (extrusion and direct), gel spinning and electro-spinning. In fact, most spinning methods require a solvent or aqueous solution for dissolving the polymer to a fluid state, except melt spinning where the polymer can be melted to a molten state. However, a melt spinning step has limitations such as an inadequate range of colored polyester chips. In this regard, there is a demand to develop a more efficient method for the spinning step such that the consumption of water is drastically reduced while providing a wider range of polyester chips to obtain the respective colored fibers. Further, other spinning processes can be utilized in yarn manufacture such as conventional ring spinning, open-end or rotor spinning, and air-jet or vortex spinning. Although rotor and air-jet spinning methods have higher production rates than ring spinning, the rotor spun yarns and air jet yarns are weaker and have a harsher feel than ring spun yarns. Further, ring spinning has a higher production cost due to its additional processes than rotor and air-jet spinning. Hence, there is a demand for affordable ring spun yarns with a decent production rate as the yarns are usually of higher quality and are produced in a fine to medium count.

Accordingly, there is a need to provide an alternative spinning process that overcomes, or at least ameliorates, one or more of the disadvantages described above. There is also a need to provide a spinning process which does not use an aqueous solution or solvent to obtain heather yarns.

SUMMARY

According to a first aspect, there is provided a method of forming a colored heather yarn having a predetermined fiber content ratio, the method including the sequential steps of (a) processing a natural fiber; (b) producing a waterless dope-dyed man-made fiber; (c) blending the individual fibers from steps (a) and (b) to produce a blended composite of fibers; and (d) roving, spinning and winding the blended composite of fibers of step (c) into a final colored heather yarn.

Advantageously, the above method may result in the formation of colored heather yarn with bleachable performance that does not utilize any water during the bleaching and/or dyeing process. The above method may also be cost efficient and may not utilize any amount of water such that the above method does not produce effluent discharge and is sustainable and eco-friendly. The above method may further prevent the excessive use of extra-long sliver (XLS) fibers to compensate the fiber breakage during the blowing room, carding and drawing processes thereby providing further cost and fiber reductions.

According to another aspect, there is provided a colored heather yarn made according to a method as defined herein.

Advantageously, the above method may result in the formation of colored heather yarn with improved quality and enhanced yarn strength. The colored heather yarn may be benzoyl peroxide safe. The colored heather yarn may also contain enhanced color effects with an enriched heather appearance under the same fiber content ratio.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to illustrate various embodiments and to explain various principles and advantages in accordance with a present embodiment.

FIGS. 1 A and B show two process flow charts of the entire system in accordance with a present embodiment from the beginning with raw cotton and polyester fibers under Ring (Combed and Carded) spinning system till the end of the process.

FIG. 2 is a process flow chart of a first passage drawing in accordance with the system disclosed in FIG. 1, where one dope-dyed recycled polyester sliver feed (101) is combined with seven raw cotton slivers feed (102), and are sent into a first passage drawing to form the first blend of colored slivers (111) having a 12.5% colored fiber content ratio.

FIG. 3 is a process flow chart of a second passage drawing in accordance with the system disclosed in FIG. 1, where two dope-dyed colored slivers feed (111) from FIG. 2 are combined with six raw cotton slivers feed (102), and are sent into a second passage drawing to form the second blend of colored slivers (121) having a 3.125% colored fiber content ratio.

FIG. 4 shows the colored fibers being entangled with a blowing room blending in accordance with the present embodiment.

FIG. 5 shows the colored fibers aligned with a general strand direction under a sliver blend in accordance with the present embodiment.

DETAILED DESCRIPTION OF DRAWINGS

Referring to FIG. 4, an illustration (400) of a blended fiber (402) shows the relatively blurred effect as the conventional dyed fiber blended at the blowing room stage is entangled with other fibers within the blend of fibers (404). The blend of fibers (404) is relatively even, therefore resulting in low visibility of the color effect, especially when the color ratio is small such as 97/3 or 95/5.

Referring to FIG. 5, an illustration (500) of a blended fiber (502) demonstrates that by feeding or blending dope-dyed recycled polyester sliver at the drawing stage advantageously provides better alignment of small percentage of colored polyester fibers such as 97/3 or 95/5 to exhibit outstanding color effects.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description.

Exemplary, non-limiting embodiments of a method for forming a colored heather yarn will now be disclosed. The method comprises the sequential steps: (a) processing a natural fiber; (b) producing a waterless dope-dyed man-made fiber; (c) blending the individual fibers from steps (a) and (b) to produce a blended composite of fibers; and (d) roving, spinning and winding the blended composite of fibers of step (c) into a final colored heather yarn; wherein the colored heather yarn comprises a predetermined fiber content ratio.

The natural fiber of step (a) may be raw cotton fiber, raw flax fiber, raw kapok fiber, raw wool fiber or raw silk fiber. The natural fiber may be raw cotton fiber and may be without any dyed colors. The method may comprise the step (a) of processing the natural fiber which comprises a process selected from a combed process or a carded process. The natural fiber of step (a) may be in the form of carded natural fiber. The natural fiber of step (a) may be in the form of combed natural fiber. The process may be selected depending on the quality, yarn count, strength and package of the final colored heather yarn.

The waterless dope-dyed man-made fiber of step (b) may comprise a waterless dope-dyed polyester fiber. The step of producing the waterless dope-dyed polyester fiber may comprise producing the waterless dope-dyed polyester fiber using waterless colored polyester chips. The step of producing the waterless dope-dyed polyester fiber may further comprise: heating the waterless colored polyester chips to a molten state; and spinning the molten polyester chips to form the waterless dope-dyed polyester fiber. The waterless colored polyester chips may be heated to an appropriate temperature where the waterless colored polyester chips become a molten state. The waterless colored polyester chips may take a period of time at the appropriate temperature to become the molten state. The molten polyester chips may be spun at a suitable time to form the waterless dope-dyed polyester fiber.

The waterless dope-dyed polyester fiber may be produced from waterless colored polyester chips. The waterless colored polyester chips may be from one or more recycled liquid-containing vessels or from one or more new liquid-containing vessels or from both. The one or more liquid-containing vessels may be made of biodegradable synthetic polyester. The biodegradable synthetic polyester may comprise polyethylene terephthalate (PET), polyhydroxyalkanoates (PHAs), poly-3-hydroxybutyrates (PHBs), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), polylactic acid (PLA), polybutylene succinate (PBS) or polycaprolactone (PCL). The one or more liquid-containing vessels may be in the form of colored or uncolored PET granules. The uncolored PET granules may be colored when specific colorants are selected, added and fixed to the uncolored PET granules via a thermodiffusion process. The thermodiffusion process may not require bleaching and may not involve water during the process. The thermodiffusion process may occur at a desirable temperature suitable for the colorant particles to be moving from one region to another region. The colored PET granules may be used as color master batch and may be in an assortment of colors.

The waterless dope-dyed man-made fiber may provide the colors for the final colored heather yarn. The colors of the waterless dope-dyed man-made fiber may be provided from the waterless colored polyester chips. The waterless colored polyester chips may be made of raw polyester chips that were dried under vacuum at a desirable temperature for a number of hours. The temperature may be in the range of about 140° C. to about 180° C., about 145° C. to about 180° C., about 150° C. to about 180° C., about 155° C. to about 180° C., about 160° C. to about 180° C., about 165° C. to about 180° C., about 170° C. to about 180° C., about 175° C. to about 180° C., about 140° C. to about 145° C., about 140° C. to about 150° C., about 140° C. to about 155° C., about 140° C. to about 160° C., about 140° C. to about 165° C., about 140° C. to about 170° C. or about 140° C. to about 175° C. The number of hours required for drying the raw polyester chips may be up to 24 hours, 22 hours, 20 hours, 18 hours, 16 hours, 14 hours, 12 hours, 10 hours, 8 hours, 6 hours, 4 hours or 2 hours. The vacuum-dried raw polyester chips may be blended with a designated amount of color master batch as mentioned above, and may be heated to an appropriate temperature, melted to molten state and spun into waterless dope-dyed man-made fibers by extrusion though a spinneret. The temperature for the raw polyester chips and the color master batch to be melted may be in the range of about 250° C. to about 300° C., about 250° C. to about 255° C., about 250° C. to about 260° C., about 250° C. to about 265° C., about 250° C. to about 270° C., about 250° C. to about 275° C., about 250° C. to about 280° C., about 250° C. to about 285° C., about 250° C. to about 290° C., about 250° C. to about 295° C., about 255° C. to about 300° C., about 260° C. to about 300° C., about 265° C. to about 300° C., about 270° C. to about 300° C., about 275° C. to about 300° C., about 280° C. to about 300° C., about 285° C. to about 300° C., about 290° C. to about 300° C. or about 295° C. to about 300° C.

The step (c) of blending the individual fibers to produce the blended composite of fibers may comprise blending about 95-97% of natural fiber with at least 3% of dope-dyed man-made fiber. The step (c) of blending the individual fibers to produce the blended composite of fibers may be undertaken to ensure proper color ratio and thus proper fiber content ratio. The step (c) of blending the individual fibers to produce the blended composite of fibers may further comprise: a first passage drawing to form a first blended fiber having a first predetermined fiber content ratio; and a second passage drawing to form a second blended fiber having a second predetermined fiber content ratio. The first passage drawing step may comprise drawing one dope-dyed polyester fiber with seven raw cotton sliver fibers to form the first blended fiber having a 12.5% colored sliver fiber content ratio. The second passage drawing step may comprise drawing two 12.5% colored sliver fibers with six raw cotton sliver fibers to form the second blended fiber having a 3.125% colored blended heather sliver fiber content ratio.

The final colored heather yarn may comprise the natural fiber having a fiber content ratio of at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96% or at least 97%.

The final colored heather yarn may comprise the waterless dope-dyed man-made fiber having a fiber content ratio of at least 10%, at least 9%, at least 8%, at least 7%, at least 6%, at least 5%, at least 4% or at least 3%.

The natural fiber of the blended composite of fibers may be processed via a carded process. The carded natural fiber of the blended composite of fibers may be spun into the colored heather yarn having a yarn size of 21/1 Ne or below. The natural fiber of the blended composite of fibers may be processed via a combed process. The combed natural fiber of the blended composite of fibers may be spun into the colored heather yarn having a yarn size of 21/1 Ne or above.

The blending of individual fibers from steps (a) and (b) in accordance with step (c) may prevent the excessive use of extra-long sliver fibers to compensate the fiber breakage during the blowing room, carding and drawing processes.

Processing in accordance with the above method is cost efficient and does not utilize any amount of water such that the above method does not produce effluent discharge and is sustainable and eco-friendly. The above method of forming a colored heather yarn further advantageously prevents the excessive use of extra-long sliver fibers to compensate the fiber breakage during the blowing room, carding and drawing processes.

Exemplary, non-limiting embodiments of a colored heather yarn fabricated in accordance with the above method will now be disclosed.

In the colored heather yarn, the predetermined fiber content ratio of the colored heather yarn may be in the range of about 80/20 to about 97/3, about 81/19 to about 97/3, about 82/18 to about 97/3, about 83/17 to about 97/3, about 84/16 to about 97/3, about 85/15 to about 97/3, about 86/14 to about 97/3, about 87/13 to about 97/3, about 88/12 to about 97/3, about 89/11 to about 97/3, about 90/10 to about 97/3, about 91/9 to about 97/3, about 92/8 to about 97/3, about 93/7 to about 97/3, about 94/6 to about 97/3, about 95/5 to about 97/3 or about 96/4 to about 97/3 of cotton fibers/other fibers.

The colored heather yarn may comprise carded natural fiber. The colored heather yarn comprising carded natural fiber of the blended composite of fibers may have a yarn count of 21/1 Ne or below that corresponds to a coarser yarn count. The colored heather yarn may have a yarn count of 21/1 Ne or below like 12.5/1 Ne. The colored heather yarn having a yarn count of 21/1 Ne or below may be used as throw blankets and/or towels.

The colored heather yarn may comprise combed natural fiber. The colored heather yarn comprising combed natural fiber of the blended composite of fibers may have a yarn count of 21/1 Ne or above that corresponds to a finer yarn count. The colored heather yarn may have a yarn count of 21/1 Ne or above like 26/1 Ne or 60/1 Ne. The colored heather yarn with a yarn count of 21/1 Ne or above may be used as shirts, light-weight shirts/blouse and/or beddings. The colored heather yarn may have a yarn count in the range of about 10/1 Ne to about 80/1 Ne, about 15/1 Ne to about 80/1 Ne, about 20/1 Ne to about 80/1 Ne, about 25/1 Ne to about 80/1 Ne, about 30/1 Ne to about 80/1 Ne, about 35/1 Ne to about 80/1 Ne, about 40/1 Ne to about 80/1 Ne, about 45/1 Ne to about 80/1 Ne, about 50/1 Ne to about 80/1 Ne, about 55/1 Ne to about 80/1 Ne, about 60/1 Ne to about 80/1 Ne, about 65/1 Ne to about 80/1 Ne, about 70/1 Ne to about 80/1 Ne, about 75/1 Ne to about 80/1 Ne, about 10/1 Ne to about 15/1 Ne, about 10/1 Ne to about 20/1 Ne, about 10/1 Ne to about 25/1 Ne, about 10/1 Ne to about 30/1 Ne, about 10/1 Ne to about 35/1 Ne, about 10/1 Ne to about 40/1 Ne, about 10/1 Ne to about 45/1 Ne, about 10/1 Ne to about 50/1 Ne, about 10/1 Ne to about 55/1 Ne, about 10/1 Ne to about 60/1 Ne, about 10/1 Ne to about 65/1 Ne, about 10/1 Ne to about 70/1 Ne or about 10/1 Ne to about 75/1 Ne.

The colored heather yarn in accordance with present embodiments advantageously provides superior quality with improved yarn strength due to its uniformity or evenness of fibers. The colored heather yarn in accordance with present embodiments also advantageously provides enhanced color effects with an enriched heather appearance under the same fiber content ratio as mentioned above. The colored heather yarn in accordance with present embodiments is also advantageously bleachable without the use of water during the bleaching and/or dyeing process and is benzoyl peroxide safe.

Definitions

The following words and terms used herein shall have the meanings indicated:

The term ‘spinning’ is to be interpreted broadly to include the textile manufacturing process where types of fiber such as cotton, flax or wool, are converted into staple yarn and then fabrics. Spinning is the process of twisting together drawn out strands of fibers to form yarn, though it is colloquially used to describe the process of drawing out, inserting the twist and winding onto bobbins. Alternatively, spinning is a process in which we convert fibers by passing them through certain processes like blowing room, carding, drawing, combing, ring frame and finally winding into yarns.

The term “ring spinning” as used herein includes the process of further drawing out roving to the final yarn count needed, inserting twist to the fibers by means of a rotating spindle and winding the yarn on a bobbin. These three stages take place simultaneously and continuously. Ring spinning is the most common spinning method in the world although it has additional processes compared to other spinning methods such as open-end spinning and air-jet spinning methods.

The term “drawing” as used herein includes the process where the fibers are blended, straightened and combined. Further, the number of fibers in the sliver is reduced or separated in order to achieve the desired linear density in the spinning process. The drawing process also improves the uniformity or evenness of the sliver. The number of drawing passages utilized depends on the spinning system used and the end products. In this regard, the raw cotton fibers and the polyester fibers are blended over two passage drawing stages to arrive at the desired fiber content ratio.

The term “blowing room” as used herein includes the process where the raw material packed in bale forms are opened, blended and cleaned, to remove the impurities on the surface of the raw material. The opening and blending processes ensure a consistent and homogenous blend of fibers such that the fabric will retain the best characteristics of each fiber. Blending can be done with either natural or manufactured fibers but usually utilizes various combinations of manufactured fibers or manufactured and natural fibers. This blended fiber is then passed through more machines to further loosen the fiber tufts and to clean and remove contaminants. In particular, the conventional heather yarns are usually prepared by blending the raw cotton with polyester fibers at the blowing room stage.

The terms “sliver fiber” and “roving” as used herein include a long bundle of fiber that is generally used to spin yarn. A sliver is created by a carding or combing process, which is then drawn into long strips where the fibers are parallel. When a sliver is drawn further and given a slight twist, it becomes roving. Alternatively, when the sliver is separated into roving, this roving is then used in the spinning process and is generally about the width of a pencil.

The terms “carded” or “carding” as used herein includes individualizing, aligning and further cleaning the fibers before reducing or condensing them into a single continuous strand of overlapping sliver fibers. In addition, a large proportion of short fibers and neps are also removed during the carding process. Accordingly, slivers that were subjected to the carding process would be considered “carded slivers”.

The terms “combed” or “combing” as used herein include the process that removes the final proportion of short fibers, neps and other impurities to create a stronger yarn. This is an optional stage, however combed yarns are usually superior in quality than carded yarns as they are generally finer, stronger, smoother and more uniform due to the removal of short fibers and the alignment of fibers. Accordingly, slivers that were subjected to the combing process would be considered “combed slivers”.

The term “colored heather yarn” as used herein includes colored blended heather yarn.

The term “Denier” or “Den” or “D” as used herein is a unit of measure for the linear mass density of fibers that is the mass in grams per 9000 meters of the fiber. Denier is more likely to be used in the United States and United Kingdom.

The term “Ne” as used herein is another measure of linear density, often known as cotton count or Number English (Ne). Under this system, the higher the numerical value, the finer the yarn. In the United States, cotton counts in the range of 1 to 20 are often referred to as coarse counts and cotton counts above 21 are referred to as fine counts.

The word “substantially” does not exclude “completely” e.g. a fiber which is “substantially free” from Y may be completely free from Y. Where necessary, the word “substantially” may be omitted from the definition of the invention.

Unless specified otherwise, the terms “comprising” and “comprise”, and grammatical variants thereof, are intended to represent “open” or “inclusive” language such that they include recited elements but also permit inclusion of additional, unrecited elements.

As used herein, the term “about”, in the context of concentrations of fiber components, typically means +/−5% of the stated value, more typically +/−4% of the stated value, more typically +/−3% of the stated value, more typically, +/−2% of the stated value, even more typically +/−1% of the stated value, and even more typically +/−0.5% of the stated value.

Throughout this disclosure, certain embodiments may be disclosed in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosed ranges. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range.

Certain embodiments may also be described broadly and generically herein. Each of the narrower species and subgeneric groupings falling within the generic disclosure also form part of the disclosure. This includes the generic description of the embodiments with a proviso or negative limitation removing any subject matter from the genus, regardless of whether or not the excised material is specifically recited herein.

EXAMPLES

Non-limiting examples of the invention and a comparative example will be further described in greater detail by reference to specific Examples, which should not be construed as in any way limiting the scope of the invention.

Example 1—Ring (Combed) Spinning System

As demonstrated in FIG. 1A, raw cotton staple fibers undergo the blowing room process to be cleaned up, and the carding process where the fibers are further cleaned up and separated. The cotton slivers are then subjected to the drawing process to improve uniformity, and finally the combing process to remove the final proportion of short fibers, neps and other impurities. At this point, the raw cotton staple fibers (95%-97%) are ready for the first passage drawing with the dope-dyed recycled polyester sliver fiber (3-5%) having a staple length of 38 mm at 1.5 Denier as shown in FIG. 1A. The polyester sliver fiber is prepared using waterless colored polyester chips heated to a molten state, and spun in the molten polyester chips into the desired staple length colored fiber. To ensure a proper fiber content ratio (97/3-95/5) during the first passage drawing stage, one dope-dyed recycled polyester colored sliver (101) is fed with seven raw cotton sliver fibers (102) to form the first blended fiber having a 12.5% colored sliver (111) fiber content ratio as shown in FIG. 2. Then two 12.5% colored sliver fibers (111) are fed with six raw cotton sliver fibers (102) at the second passage drawing stage to form the second blended fiber having a 3.125% colored heather sliver (121) fiber content ratio as shown in FIG. 3. The combined blended heather sliver is then subjected to the roving stage where the sliver needs to be condensed or reduced into a finer strand known as a roving before it can be spun into a yarn. The roving frame draws out the sliver to a thickness of a few millimetres and inserts a small amount of twist to keep the fibers together. Finally, the desired heather yarns with a yarn size finer than 21/1 Ne, especially 60/1 Ne, that are rarely available in the commercial market (labelled as 95/5-97/3 cotton/others) are prepared from the ring spinning and winding processes.

Example 2—Ring (Carded) Spinning System

As demonstrated in Example 1 and FIG. 1B, similarly, the raw cotton staple fibers undergo the blowing room process to be cleaned up, and the fibers are further cleaned up and separated during the carding process. At this point, the raw cotton staple fibers (95%-97%) are ready for the first passage drawing with the dope-dyed recycled polyester sliver fiber (3-5%) having a staple length of 38 mm at 1.5 Denier as shown in FIG. 1B. The polyester sliver fiber is prepared using waterless colored polyester chips, heated to a molten state, and spun in the molten polyester chips into the desired staple length fiber. To ensure a proper fiber content ratio (97/3-95/5) during the first passage drawing stage, one dope-dyed recycled polyester colored sliver (101) is fed with seven raw cotton slivers (102) to form the first blended fiber having a 12.5% colored sliver (111) fiber content ratio as shown in FIG. 2. Then two 12.5% colored slivers (111) are fed with six raw cotton slivers (102) at the second passage drawing stage to form the second blended fiber having a 3.125% colored heather sliver (121) fiber content ratio as shown in FIG. 3. The combined blended heather sliver is then subjected to the roving stage where the sliver needs to be condensed or reduced into a finer strand known as a roving before it can be spun into a yarn. The roving frame draws out the sliver to a thickness of a few millimetres and inserts a small amount of twist to keep the fibers together. Finally, the desired heather yarns with yarn size like 21/1 Ne or coarser (labelled as 95/5-97/3 cotton/others) are prepared after the ring spinning and winding processes.

INDUSTRIAL APPLICABILITY

The colored heather yarn having a yarn count of 21/1 Ne or below may be coarser. The colored heather yarn may have a yarn count of 21/1 Ne or below like 12.5/1 Ne. The colored heather yarn having a yarn count of 21/1 Ne or below may be spun into fabric with a coarser and harsher feel. The colored heather yarn having a coarser yarn count may be used as throw blankets and/or towels.

The colored heather yarn having a yarn count of 21/1 Ne or above may be finer. The colored heather yarn may have a yarn count of 21/1 Ne or above like 26/1 Ne or 60/1 Ne. The colored heather yarn having a yarn count of 21/1 Ne or above may be spun into fabric with a finer and smoother feel. The colored heather yarn having a finer yarn count may be used as shirts, light-weight shirts/blouses and/or beddings The colored heather yarn having a yarn count of 21/1 Ne or above may be spun into fabric having superior quality, stronger and more uniform yarn. The colored heather yarn having a yarn count of 21/1 Ne or above especially 60/1 Ne may be commercially available at an affordable cost.

It will be apparent that various other modifications and adaptations of the invention will be apparent to the person skilled in the art after reading the foregoing disclosure without departing from the spirit and scope of the invention and it is intended that all such modifications and adaptations come within the scope of the appended claims. 

What is claimed is:
 1. A method of forming a colored heather yarn, comprising the sequential steps: a) processing a natural fiber; b) producing a waterless dope-dyed man-made fiber; c) blending the individual fibers from steps (a) and (b) to produce a blended composite of fibers; and d) roving, spinning and winding the blended composite of fibers of step (c) into a final colored heather yarn; wherein the colored heather yarn comprises a predetermined fiber content ratio.
 2. The method according to claim 1, wherein said natural fiber is a raw cotton fiber.
 3. The method according to claim 1, wherein the step (a) of processing said natural fiber comprises a process selected from a combed process or a carded process.
 4. The method according to claim 1, wherein said waterless dope-dyed man-made fiber of step (b) comprises a waterless dope-dyed polyester fiber.
 5. The method according to claim 4, wherein the step of producing the waterless dope-dyed polyester fiber comprises producing the waterless dope-dyed polyester fiber using waterless colored polyester chips.
 6. The method according to claim 5, wherein the step of producing the waterless dope-dyed polyester fiber comprises: heating said waterless colored polyester chips to a molten state; and spinning the molten polyester chips to form said waterless dope-dyed polyester fiber.
 7. The method according to claim 5, wherein said waterless colored polyester chips are from one or more liquid-containing vessels.
 8. The method according to claim 7, wherein said one or more liquid-containing vessels are made of a biodegradable synthetic polyester.
 9. The method according to claim 8, wherein said one or more liquid-containing vessels comprise said biodegradable synthetic polyester selected from the group consisting of polyethylene terephthalate (PET), polyhydroxyalkanoates (PHAs), poly-3-hydroxybutyrates (PHBs), polyhydroxyvalerate (PHV), polyhydroxyhexanoate (PHH), polylactic acid (PLA), polybutylene succinate (PBS) and polycaprolactone (PCL).
 10. The method according to claim 9, wherein said one or more liquid-containing vessels are in the form of colored or uncolored PET granules.
 11. The method according to claim 10, wherein the step of producing the colored PET granules comprises selecting specific colorants; and adding and fixing said selected specific colorants to said uncolored PET granules by a thermodiffusion process.
 12. The method according to claim 1, wherein the step (c) of blending the individual fibers to produce the blended composite of fibers comprises blending about 95-97% of natural fiber with at least 3% of dope-dyed man-made fiber.
 13. The method according to claim 1, wherein the step (c) of blending the individual fibers to produce the blended composite of fibers comprises: a first passage drawing to form a first blended fiber having a first predetermined fiber content ratio; and a second passage drawing to form a second blended fiber having a second predetermined fiber content ratio.
 14. The method according to claim 13, wherein said first passage drawing step comprises drawing one dope-dyed polyester fiber with seven raw cotton sliver fibers to form the first blended fiber having a 12.5% colored sliver fiber content ratio.
 15. The method according to claim 13, wherein said second passage drawing step comprises drawing two 12.5% colored sliver fibers with six raw cotton sliver fibers to form the second blended fiber having a 3.125% colored blended heather sliver fiber content ratio.
 16. The method according to claim 14, wherein said second passage drawing step comprises drawing two 12.5% colored sliver fibers with six raw cotton sliver fibers to form the second blended fiber having a 3.125% colored blended heather sliver fiber content ratio.
 17. A colored heather yarn made according to the method of claim
 1. 18. The colored heather yarn according to claim 17, wherein the predetermined fiber content ratio of the colored heather yarn is in the range of 95/5 to 97/3 cotton/others.
 19. The colored heather yarn according to claim 17, wherein the colored heather yarn has a yarn count of 21/1 Ne or coarser.
 20. The colored heather yarn according to claim 17, wherein the colored heather yarn has a yarn count of 21/1 Ne or finer. 